I don't think it would really be worth that much at this point, so unless you need the cash, I'd install CFW as other people are suggesting. You should look into it regardless of your decision; I'm sure the process is straight-forward.
I had an R4, I believe it was, for my DS(both times I bought one), and it didn't keep me interested enough to not sell it, but now, several years later, I wish I didn't sell it because I get a hankering for Pokemon quite a bit, and even with a controller, emulators don't fill my fix. I can play on a DS(or 3DS) whenever and wherever I want. I can have it running on my desk while I'm doing stuff at the computer, I can take it with me if I go visit friends or when I go to the bathroom, laying in bed when I'm about to fall asleep and when I'm waking up, etc. Having access to an emulator is nice, but again, it's just not the same. I even miss the touchpad and to a lesser extent, the stylus, whenever I'm playing on an emulator.
The biggest difference I see(because let's face it, most games on the DS and 3DS aren't interesting or good enough to justify saving the system for), is Pokemon. I've been playing it since I was little, I collected and battled cards, participated in a lot of the promotional stuff like with Burger King, etc. I think I've played every game, even the third of each generation(Yellow, Crystal, Emerald, etc.) until X/Y. I played Diamond and Platinum competitively against people on forums, spent hundreds of hours hatching eggs for good IVs and natures and abilities, cross-bred for specific egg moves, hunted for shinies, etc.
I'm a big fan of the grind and goal of perfectly(or at least optimized) training of Pokemon to make the rest of the game and metagame easier. The only problem I have is with collecting the Pokemon. Because they're not all available in a single game, and there are over 500 at this point, I'll never complete the Pokedex, so I do eventually get bored. There really is a rich metagame, that usually gives me 100 hours of entertainment, but again, I enjoy the kind of grind that is the Pokemon metagame. I remember hatching somewhere around 800 Charmander eggs in Pokemon X looking for a shiny with a good nature just because I wanted a black Charizard.